On Wednesday, Brown approved the board’s recommendation to appoint Koko in the position, saying he has a wealth of experience and understands Eskom’s challenges.
It comes after Brian Molefe resigned earlier this month following evidence of his relationship with the Gupta family and questionable deals made in the public protector's state of capture report.
Koko has been speaking on behalf of the utility since Molefe’s sudden resignation - particularly about issues pertaining to the nuclear build program.
At the same time, Brown says the board must start looking for a permanent CEO.